Pictures whether photo's, drawings or animations can be presented in a lot of ways. Sliders are used on several pages in several ways on this site. Mostly this gives the website a nice appearance but it distracts from the pictures itself. If you have a webshop or you are a painter selling your art you probably better of with a more static presentation.
Building a gallery is not the most time consuming part of building websites. If however all pictures need to be standardised the editing work might be quite intensive. Sizing of pictures to the same size and colour scheme adapted for a good presentation, editing like removing backgrounds or unifying colour scheme. If your website is in black and white for instance all pictures might need to adapt to grayscale.
Look at the first example of pictures underneath: Due to different sizes of the pictures the widget (box around the pictures) changes size accordingly. Technically all is well, but from a design point of view this needs optimising. The second widget has pictures in the same size and lay-out. From a design point this is to be preferred.
I can do the editing for you with use of photoshop and/or other tools. If it involves a large amount of pictures it might be done by automation (actions) the handling. Especially for webshops or sites aimed at selling like real-estate you will want to have a uniform way of presenting your pictures.
There are a lot of different way's to present images. In general try to stick to one way of presenting them. Your format / template of pages will not only be easier to maintain, your viewers will recognise the feel of your website after some time. Beware of making things to complicated. Designing your website in black and white for instance : It's popular from a design point since it looks smooth and straightforward. Your picture material might not be suited to black and white - like the colorful photo's of Tobago - and even Photoshop might not get you what you really want.
One sort of picture is special in it's own way. The background picture. Wonders can be achieved using it. If however your site is looked at through different resolutions and devices the behavior and view of a background might distract more than a simple colored or plain background. In general putting pictures in the background of tekst might also decrease readability of your content.
Even with adjusting the color of fonts background pictures tend to make readability a problem. If your site is not always looked at the same - preferred high - resolution (which goes for nearly all websites), backgrounds might be scaled and become to blurred, or you might only see parts of the total picture and loose the intended effect of a background.
If backgrounds are already to be used try to avoid putting text or images over it and use this only for graphical design.